If you know why they don’t want you it is probably not worth pursuing. You will probably not change their minds. If they are looking for big bucks and you don’t come with big bucks they are not going to change their minds. If they are looking for a serious learner and you don’t fit the bill, they are not going to change their minds. If they know something about you that they find offensive they are not going to change their minds. The only way they will reconsider is if a few years go by and the two of you are still hanging around.
If you don’t know why they don’t want you, then it might be worth finding out. They might NOT have a valid reason, and you might just need the right shadchan or Rabbi to make this dream a reality.
Only you know the truth about your particular situation. Don’t try to fool yourself if you really, truly don’t have a chance with this girl. There are so many wonderful girls out there who are just waiting for a great guy to call them, so don’t go chasing after someone who won’t give you the time of day. Hatzlocha.